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UNITED STATES EDWARD A. DIETERLE AND sAUI; n. .SEMENOW, or PITTSBURGH,,PnfNu'sYLvAnm,

ASSIGNORS TO THE KOPPERS COMPA CORPORATION OF PENNSYLVANIA.

NY, or PITTSBURGH, PENNSYLVANIA, n

PURIFICATION OF LIQUIDS.

T 0 all-whom it may concern Be it known that we, EDWARD A. DIETERLE andSAUL D. SEMnNoW, both citizens of the United States, and both residingat Pittsburgh, Allegheny county, Pennsylvania, have invented a new anduseful Improve-- ment in Purification of Liquids, of which the followingis a full, clear, and exact description.

The present invention relates to the purification of liquids andparticularly to the purification of the waste liquors from industrialplants so that they may be discharged into strean is without pollutingthe stream water. The invention is described with particular referenceto its embodiment in a process of purifying the waste liquor from theammonia stills of the by-product coke industry.

.It is to be understood, however, that the invention is not limited inits application to this industry but may be otherwise employed.

Referring to the process as employed for treating the waste ammoniastill l1quor:-

The raw ammonia still waste has objectionable properties which should beremoved before it is discharged into a stream, in order to prevent thepollution of the water thereby. The objectionable properties of theammonia still-,waste are its harmful efdrained, the presence, of thesesalts is not 1 particularly objectionable; The present I process has-todo particularly with thei-"removal of those substances of theammoniastill waste Whichgive itits harmful eflect on fish, its disagreeableodor and taste and its dark color.

The ammonia still waste liquor is drawn' from the still hot and whilehot is aerated, preferably by running it through an aera-- Specificationof Letters Patent.

Patented Dec. 2, 1919..

' Application filed February 15, 1919. Serial No. 277,118}. 1

tion tower filled with baffles, coke or other material over which theliquor-trickles in contact with the air. This causes some evaporation ofthe water and thereby concentrates theliquor to some extent. It alsopermitsthe evaporation of some of the volatile constituents of theliquid and thereby gets rid of some of the disagreeable odor. Theaeration of the liquid also causes a more ready precipitation of thesolids in the subsequent step of treatment in the settling tank. While-it is preferred to aerate the liquor, this step may be omitted. i 1 Theliquor is next run into a settling tan where it remains for abouttwenty-four hours. During this time about 95% ofthe precipitable :solidssettle out of the liquid.

The liquid is drawn next from the settling tank and filtered through aninorganic material, preferably granulated blast furnace slag. Thisfiltration completes thgremoval of the solids which do not settle out inthe settling tank' and also removes the tarry matter from the liquor andif the slag employed contains iron oxide such as are found in the. spentslag whi h results from the treatment of mine water by the process'ofthe Heckman patent, 1,171,046, of February 8th, L916, the'sulfids arealso removed from principally as calcium sulfids. blast furnace slagalso partially removes oxids resulting f'rom'the treatment of mine wateror the'like, the iron oxids might be otherwise supplied to the slag or,jnor a nic filtering material usedfor this. step 0 the process. i

The filtered li'quor may be treated for the removal and recovery ofcyanogen com- This preferably accomplished by theiadditionto the liquorof a compound, such as a ferrous salt, which will precipitateftheferrocyanids followed by the addition of cupric' sulfate and ferroussulfate, which results in the precipitation of onthe liquor. The sulfidsexist in the liquor The spent '85 some of the cyanogen com oundm'While-it.

is preferred to use the s ag with the iron prous thiocyanate. This stepmay be omitted I ifdesirell.

The above recited stepsar'e pose of preliminarily clarifying'the liquor,

whereby thaburden placed u-pon'tlie peat filter bed is lessened.

The next stepin the process for the puristhe treat-4 the liquor througha mass of peat.

ment of the liquor with peat. This treatment is preferably carried outby filtering Vile have found that a filter bed of peat a foot or moreinthickness is satisfactory. Such filtration permits a rapid treatment ofthe liquor and effects a maximum removal of the phenoloid bodies with an'linimnm of filtering material. This treatment results in the finalseparation of the remaining constituents which gave the liquor itsharmful qualities, disagreeable taste, smell and dark color. The liquorafter the peat treatment is substantially colorless and substantiallyodorless, and when diluted in the stream is non-poisonous to fish lifeand not harmful to the water for drinking purposes.

Certain industrial .waste liquors which contain a minimum of solidimpurities, sulfur and cyanogen compounds, for example the efiiuentsfrom certain ainmonia stills, may be treated directly with the peatwithout any preliminary treatment of the liquor. The liquor purified bythe peat treatment, may if desired, be passed through an earth filterbed to effect a more complete removal of impurities before flowing intothe stream.

While .the preferred embodiment of the invention has been specificallydescribed, it

is to be understood that the invention is not limited to such embodimentand that some of the steps may be omitted and other variations may bemade within the scope of the following claims We claim:

1. The herein described process of purifying liquors containingphenoloid bodies,

comprising, filtering the material through a filter bed containing peat;substantially as described.

2. The herein described process of purifying Waste ammonia stillliquors, comprising. preliminarily clarifying the liquor and thenfiltering it through a filter bed containing peat; substantially asdescribed.

3. The process of purifying waste ammonia still liquors which consistsin aerating the liquor, separating the solids therefrom by settling,filtering the liquor through an inorganic filtering material and thenfiltering the liquor through a filter bed containing peat; substantiallyas described.

4. The process of purifying waste ammonia still liquors, comprising,treating the liquor with an iron oXid-containing material, andthereafter filtering the liquor through a filter bed containing peat;sub= stantially as described.

5. The process of purifying waste ammonia still liquors, comprising,filtering the liquor through-blast furnace slag and thereafter filteringthe liquor through a filter bed containing peat; substantially asdescribed. (i. The herein described process of purif v ing waste ammoniastill liquors, comprising, preliminarily filtering the liquor, re movingthe cyanogen compounds from the liquor, and thereafter filtering theliquor through a filter bed containing peat; substantially as described.

In testimony whereof we. have hereunto set our hands.

EDWARD A. DIETERLE. SAUL D. SEMENOVV.

